FR2573986A1 - DEVICE AND METHOD FOR TRANSLUMINAL IMPLANTATION - Google Patents

Abstract

THE INVENTION RELATES TO AN IMPLANTATION DEVICE. IT RELATES TO A DEVICE INCLUDING A PROBE 1 AROUND WHICH A PROSTHESIS 2 IS PLACED, WHICH IS ITSELF SURROUNDED BY A DOUBLE WALL TRUNK 51, 52 OF A FLEXIBLE PIPING 5, THIS DOUBLE WALL TRUNK BEING FORMED BY A WINDING OF THE PIPING ON ITSELF. DURING FITTING, THE FLEXIBLE PIPING IS UNLOADED ON ITSELF SO THAT IT EXERCISES NO FRICTION FORCE ON PROSTHESIS 2 WHICH CAN THEN EXPAND AGAINST THE VESSEL WALLS. APPLICATION TO THE REFECTION OF VEINS AND ARTERIES.

Description

The present invention relates to a method and a

  Transluminal implanting device of a sensory implant

  sibly tubular, expandable and preferably attached

  automatic, such as a graft or prosthesis.

  In known devices of this type intended for the introduction of expandable prostheses for example into a blood vessel or other narrow passage, disadvantages exist. Such a disadvantage is due to the fact that a clamping device surrounding the prosthesis during insertion can damage the vessel wall as the clamping device widens to release the prosthesis. When the clamping device is then of the ejector type, the friction, for example between the prosthesis and the clamping device, may make it difficult to eject the prosthesis or may cause deterioration thereof. When the prosthesis is squeezed radially during insertion to expand when released, the friction is further enhanced. Friction reduction tests using exposed lubricant on the prosthesis side or the passage wall may not be convenient under many conditions. In many cases, the space required for the clamping device is a hindrance and it often happens that the clamping device and its operating elements are of a complex nature

  presenting an associated risk of malfunction.

  These disadvantages are particularly present during the implantation of a prosthetic graft in a vein, an artery or the like. The term "expandable prosthesis" denotes a tubular device forming, for example, a complement of an artery, a vein or the like,

  this prosthesis being introduced in the compressed state radia-

  can then expand radially at the location

implantation cement.

  ; The invention thus relates to the production of a device of the type indicated above, not exhibiting or reducing at least some of the aforementioned drawbacks while having corresponding advantages, compared with

known devices.

  Another advantage of the invention is the production of a device allowing transluminal implantation of small diameter expandable prosthesis so that it

  can be implanted by percutaneous introduction.

  It also relates to a device comprising an inflatable balloon intended to widen the front opening

implantation of the prosthesis.

  More specifically, the invention relates to a device

  tif particularly useful for translumi-

  nale of an expandable prosthesis that automatically attaches itself.

  The device according to the invention comprises such a prosthesis and, concentrically with it, a flexible probe having a device allowing the prosthesis to be maintained in a radially contracted state and its release at the desired location of a passage or an opening, this device being such that its device for holding and releasing the prosthesis comprises a flexible tube surrounding the probe and having a first end connected to the probe, this flexible tube being folded inside itself to that it forms a double wall section radially surrounding the prosthesis and preferably having the same length substantially, the prosthesis being able to be released by a relative axial displacement of the ends

flexible piping.

  The first end of the flexible pipe is preferably that of the inner wall of the double wall section, in a radial representation. With this arrangement, the friction between the prosthesis and the flexible tubing, during the release operation, is zero because the flexible tubing separates from the

prosthesis by unwinding.

  The prosthesis is substantially tubular and is arranged to radially surround the probe, the section of double-walled flexible tubing surrounding the prosthesis at the time of introduction. The probe has for

  role of guiding the prosthesis during the introductory

  tion. This probe, which is advantageously flexible and may be formed of a suitable material such as a polymer, may comprise an opening axial channel through which a fluid, for example a contrast liquid, may be introduced to the desired location, in the region of

the front end of the probe.

  The double-walled pipe section is thus arranged so that it radially surrounds the prosthesis. The flexible tubing is preferably formed

  a material whose surface is flexible and deformable.

  The section of flexible pipework intended to form the double-walled section at least is preferably

  made of polyethylene or polyvinyl chloride.

  The double-walled flexible pipe section is thus intended to retain a radially compressible prosthesis in a contracted state during insertion, the prosthesis, after its release, being able to expand to a normal dimension so that it is in contact

of the vessel wall.

  An end surface of the probe and the double-walled section may be arranged to delimit a cavity in which the prosthesis is housed

during the introduction.

  In a preferred embodiment of the device, the flexible tubing is sealed, its two ends being connected to the probe, and the surface of the probe adjacent to the flexible tubing, between the end connections of the flexible tubing, are sealed if although the flexible piping and the probe form a chamber. A lubricant can be introduced into this chamber, particularly in the section of flexible pipe

  forming the double-walled section, so that the lubricant

  It reduces the friction between the inner wall and the outer wall of the double-walled section during the release of the object. The lubricant is thus enclosed in the chamber and it is exposed neither to the prosthesis nor to the space in which the prosthesis is released. As the location difficult to access is constituted by a chosen place in a channel or an opening, for example a vein, an artery or the like in a living organism and as one can not take

  the risk of leakage from the chamber could expose the

  In order to reduce the contact pressure between the lubricant and the lubricant, a fluid such as a blood and physiological saline substitute can be introduced and put under pressure in place of the lubricant. the walls of the flexible pipe in the double wall section so that the friction between the inner and outer walls is reduced during the relative axial displacement of the walls. The fold of the flexible pipe, in the direction of introduction of the probe, can be forward

  where the first end of the pipe

  The flexible substrate is connected to the probe so that when the prosthesis is released by a pulling force applied to the other end of the flexible tubing, relative to

  at the probe, the fold moves to the connecting position

flexible piping.

  The probe, at its insertion end, may comprise a sleeve which surrounds it coaxially and against which is fixed the inner wall of the double-walled section. The sleeve may be movable axially with respect to the probe and may have, at its front end in the insertion direction of the probe, a cavity which houses

  the end section of the prosthesis at the time of insertion

  duction. A flange attached to the probe is intended to form a bearing shoulder of the end of the graft placed in the cavity, so that when the other end of the flexible pipe is set back, the sleeve and thus the wall of the surrounding cavity moves away from the propthesis. The sleeve and the flange thus form an ejector device which is controlled towards the end of the release operation. The wall surface of the cavity turned radially towards the prosthesis is advantageously formed of a material having a low coefficient of friction relative to the prosthesis, for example "Teflon". The flexible tubing is suitably secured at the sleeve, at a location between the ends of the flexible tubing so that the first end of the flexible tubing is connected sufficiently closely to the probe. The flexible tubing is preferably attached to the sleeve behind the front edge thereof in the insertion direction of the probe. In this manner, the pleat of the flexible tubing recedes to a position behind the free edge of the cavity before further movement of the recessed flexible tubing returns the sleeve away from the prosthesis. The other end of the flexible pipe is advantageously connected tightly to the probe by

  a sealing device for moving axially

relative to the probe.

  - The front end of the probe can carry a rounded ball forming a head for the probe and facilitating the penetration thereof to the desired location. The

  ball may have a passage connected to the channel of the probe.

  The ball may have a diameter approximately equal to the outer diameter of the double-walled section when it surrounds the prosthesis. The ball may be formed of a metal so that the detection of the front end of the probe by

  x-ray is facilitated during the introduction.

  The flexible pipe can be folded over

  even so that it forms a double-walled stretch surrounding

the probe.

  Flexible tubing may have a larger diameter section and thus form the wall

  radially outer section double wall.

  The fold of the flexible pipe connecting the walls of the double-walled section may be turned away from the insertion end of the probe so that the end of the annular prosthesis facing the insertion end of the the probe is exposed last when moving the other end of

flexible tubing.

  In the latter case, when the prosthesis is released, the other end of the flexible tubing can be held permanently and the probe is pushed forward in the insertion direction, the prosthesis being fixed axially with respect to the surrounding parts of the

  probe during the release operation.

  In the case where the fold of the flexible pipe connecting the walls of the double-walled section is arranged forward in the insertion direction of the probe, the probe can be held fixed during the release of the prosthesis and a traction force can be applied to the other end of the flexible tubing, the prosthesis being fixed axially relative to the surrounding parts

  of the probe during the release operation.

  As indicated above, the device according to the invention may comprise an inflatable balloon intended to

  to widen the canal before implantation of the prosthesis.

  This balloon can be constituted by the outer wall of the double-walled section which, after swelling, allows

  enlargement prior to implantation.

  In another embodiment of the invention,

  the inflatable balloon can be placed in front of the double-walled section or behind this double-walled section, so that it ensures the desired enlargement of the vessel

  before releasing the prosthesis at the desired location.

  In another embodiment of the invention, the inflatable balloon may be placed around the double-walled section and may be of substantially the same length

that this one.

  The invention also relates to a method for implanting

  transluminal delivery of a substantially tubular, expandable and self-fastening prosthesis, which method comprises the following operations:

  a) The provision of the prosthesis in a radi-

  It is contracted around an elongated flexible probe, at a first end thereof, and in a double-walled section of a flexible pipe placed around the section and preferably having substantially the same length as the latter, the section being formed by folding one end of the tubing into itself and attaching the end to the probe, b) transferring the assembly including the prosthesis, the probe and the flexible tubing to the desired location inside the canal, c) releasing the prosthesis at this location by axially moving the other end of the flexible tubing relative to the probe so that the prosthesis can expand radially and attach itself automatically at the corresponding location, and d) extraction of the probe and flexible tubing, the remaining prosthesis at the corresponding location

in the channel.

  In such a transluminal implantation method, for example in the case of stenosis, the canal may be enlarged at said location before release and implantation of the prosthesis at this location so that a new stenosis caused by the prosthesis acting as a restraining member is avoided. In one embodiment

  preferred embodiment of the invention, the translu-

minal is percutaneous.

  Other features and advantages of the invention

  tion will become more apparent from the following description,

  with reference to the accompanying drawings in which: Figure 1 is a schematic axial section of a device according to the invention; Figure 2 is an axial section of the front portion of another embodiment of the device according to the invention, in a first working position; Figure 3 is an axial section of the device of Figure 2, in a second working position;

  FIG. 4 is a partial axial sectional schematic

  tick of a variant of the device according to the invention; Figure 5 is a schematic axial section of another alternative device according to the invention; Figure 6 is an enlarged partial schematic sectional view of the device of Figure 5, in a specific working position; Figure 7 shows a variant of the device of Figure 6; Figure 8 is a schematic side elevation

  another embodiment of the device according to

  vention; FIG. 9 is a schematic side elevation of another embodiment of the invention

  Figure 10 is a schematic side elevation

  another embodiment of the invention; and FIG. 11 is a section along the line

A-A of Figure 10.

  FIG. 1 represents a device intended for the implantation of a graft or expandable prosthesis 2, in

  living organism, in a location that is difficult to access

  possible, for example at a desired location of a vein or artery, the graft 2 being intended to strengthen

  a defective section of the vein or artery.

  The device generally comprises a set 100 forming a probe, having, at its insertion end, a device 200 for clamping and transporting

a prosthesis or graft 2.

  The device comprises a flexible and elongated probe

  l preferably having an axial channel 4 which opens.

  The probe tube 1 is flexible and is for example formed of "nylon". At its front end, the tube 1 has a rounded head 3 in which the channel 4 extends.

  facilitates the introduction of the device into a narrow channel.

  Flexible pipe 5 is fixed firmly and permanently, at its end 7, to the outer surface of the tube 1. The flexible pipe 5 which is soft and which is for example formed of polyethylene, is turned on itself by evagination so that it forms a double-walled section of flexible pipe whose inner wall, radially, forms the end 7. The graft 2 is an element

  radially compressible tubular configuration

  the outer end of tube 1 and is surrounded by

  by a section 51, 52 with double wall of the pipework 5.

  The fold 6 of the double-walled section 51, 52 moves along the piping to the attachment location of the end 7 of the pipework when the other end of this pipework 5 (on the right in FIG. to tube 1) is drawn. In this way, no slippage exists between the graft 2 and the wall 51 of the flexible pipe. When moving the fold 6 to the right in Figure 1, the graft 2 is exposed in the axial direction and can expand and thus come into contact with the surface 13 of a vein or artery (see Figure 2). The other

  end of the flexible pipe 5 is connected

  temen- to the outer face of the tube 1. The pipe 5 is coaxially connected to a flexible operating tube formed of a helical spring 8 made of stainless steel, the spring 8 being externally covered with a chamber

  removable: narrow bead formed for example polychloride

  vinvle. This enclosure or sheath 9 is connected tightly to the polyethylene tube by a connector 15. A sleeve surrounds the tube 1 and is rigidly connected to the spring 8 and is connected tightly to the enclosure 9. The other

  end of the sleeve has an O-ring 12 ensuring the

  The pipe 1, the pipe 5, the enclosure 9, the sleeve 10 and the seal 12 thus form a closed chamber 25. The sleeve 10 has a hole 14 passing through the wall of the sleeve and forming a channel through which a fluid 22, for example physiological saline, a blood substitute,

  air or the like, may be introduced and placed under

  In this way, fluid 22 can penetrate between the walls 51, 52 of the flexible tubing and separate them so that they can move axially.

  one with respect to the other with a very reduced friction.

  The channel 4 of the tube 1 can be used for the introduction of a contrast medium into the area surrounding the front end of the device, so that the position of the device can be easily detected.

  for example using a radiographic technique.

  When the graft 2 is to be released, the operator, with one hand, can hold the rear end of the tube 1 and, with the other hand, pull the sleeve 10, in the direction of the arrow 20 , the fold 6 of the piping

  flexible 5 returning and releasing the transplant 2.

  The insertion direction of the device is indicated

by the arrow 23 in FIG.

  When the graft 2 is of the type that comprises a tubular sleeve armed with a helical wire, the ends of the reinforcing wire, at the rear end of the graft 2, are only weakly likely to perforate the pipe 5 during the release. from the back end

  2. This risk can be eliminated by improving

  of the invention, the corresponding device being realized in the manner clearly shown on the

Figures 2 and 3.

  In FIGS. 2 and 3, the corresponding details

  those of Figure 1 bear the same numerical references

  HAZARD. The tube 1 comprises, at its front end, an annular flange 60 having a hub 61 permanently connected against the outer face of the tube 1. A sleeve 55 surrounds the hub 61 and its axial displacement relative to the flange is controlled by this hub. The flange 60 constitutes a stop for the sleeve 55, in the direction of introduction of the device 23. The sleeve 55 comprises, at its front end, a permanently connected section of tube 55 formed of a material having a low coefficient of friction with the graft 2 preferably consisting of "Teflon". When the sleeve 55 is in its advanced position (Figure 2), the section 56 of the tube and the flange delimit a cavity 57 aui lodge the rear end of the graft 2 which is radially compressed. The inner wall 51 of the double-walled section is fixed against the periphery of the sleeve 55. The anchoring is ensured by

11 -

  a circumferential cavity 54 -formed in the outer wall of the sleeve 55. The link 53 placed around it squeezes the wall 51 of the pipe in the cavity. When the pipe 5 is pulled backwards so that the fold 6 moves to the right, this fold 6 passes on the

  section 56 of tube and goes back to the circumferential cavity

  54 of the sleeve. Further removal of the pipe

  flexible earth 5 causes the withdrawal of the sleeve 55 and thus the section 56 of "Teflon" tube relative to the flange 56, the rear end of the graft 2 being exposed and able to expand radially without risk of perforation

flexible piping 5.

  FIG. 4 represents the front end of a variant of the device according to the invention. The device comprises an elongated flexible probe 1 surrounded coaxially by a flexible pipe 5, a first end 7 of which is permanently and tightly connected to the outer face of the probe 1. The flexible pipe 5 is turned on itself by evagination so that it forms a double-walled section 51, 52 placed in front of the surface 70 of the front end of the probe 1. This surface 70 and the section 51, 52 form a cavity housing the graft 2. This is released by applying pulling forces to the other end of the pipework 5 (towards the

right in Figure 4).

  FIGS. 5 and 6 show an example of a device whose details corresponding to those of the preceding figures bear the same numerical references. In addition, Figure 5 indicates that the flexible pipe 5 has a section 50 of enlarged diameter. When the flexible pipe 5 is turned back on itself and forms a double-walled section 51, 52 surrounding the tubular graft 2, the larger-diameter section forms the outer wall 52 of the double-walled section 51, 52

(Figure 6).

  Thanks to this provision, it is not neces-

  that the flexible pipe 5 is expanded radially to accommodate the graft 2, between the double wall section 51, 52 and the section surrounding the probe 1 is placed radially.

towards the inside.

  Figures 5 and 6 show the first end or front end of the flexible pipe connected to the front end of the probe as indicated by reference 7, the fold being intended to be behind the connection position 7, in the direction 23 probe introduction, so that the fold 6 deviates

  this position when the graft is released by application

  cation of tensile forces at the other end of the

  flexible pipe 5, with respect to the probe 1.

  Figure 1 shows graft 2 placed directly

  contact with probe 1, while FIGS. 5 and 6 show the graft placed around a stump

  58 of flexible piping directly surrounding the probe 1.

  The fold 16 formed between the sections 58 and 51 of flexible pipework are normally relatively at rest relative to the probe 1 whereas it can be considered that the fold 16 determines the position at which the end

  before the flexible pipe 5 is connected to the probe 1.

  FIG. 6 shows the section 51, 52 with a double wall positioned so that the fold 6 is opposite.

from the front end of the probe.

  It should be noted, however, that section 51, 52

  can be turned over so that fold 6 turns its back on the ex-

  front end of the probe as shown in Figure 7. In this case, the graft 2 can be released from its rear end. This possibility is interesting when the graft must for example be implanted in an artery traversed by blood in the opposite direction to the sense

introduction of the probe.

  In this way, the risk presented by the

  Figure 6 and due to the fact that the current 200

  can fold the end of the graft that is first ex-

  posed and expands, is avoided.

  It is usually necessary to determine that the graft is fixed relative to the surrounding elements during the release operation. In the arrangements of FIGS. 1 and 6, this characteristic can be obtained by fixed holding of the probe 1 with respect to the elements which surround it and by withdrawal of the end of the pipe.

  flexible field during the release operation.

  In the arrangement shown in FIG. 7, the preceding characteristic is obtained by fixed retention of the rear end of the flexible pipework and by displacement of the probe 1 towards the front, in the insertion direction. FIG. 5 represents the rear end of the probe 1 fixed in a housing 80 having a chamber 81 which communicates with a channel 4 of the probe 1. A channel 84 passes through the wall of the housing 80 and communicates with a chamber 81 so that the fluid 21 be introduced into

  the region of the front end of the probe.

  The housing 80 also has an opening provided with

  a seal 82, similar to an O-ring.

  A rod 30 passes through the channel 4 of the probe 1, into the chamber 81 of the casing 80 and into the sealing device 82, and is surrounded in a sealed manner

  by the sealing device 82. Section 31 of the

  mite before the rod 30 is folded a half turn with

  a radius of curvature which corresponds for example to approximately

  to the diameter of the probe 1.

  The stem 30 is suitably elastic

  so that the section of its front end, during the introduction

  duction of the probe, can fold the front part of the probe. In this regard, the rod 30 can be pulled in such a way that the end section 31 is pulled into the a part of the probe 1 with folding thereof under the combined action of the elastic resistance to the bending of the probe 1 and end section 31. The importance of the curvature of the end portion of the probe may vary by rotation of the rod 30, and the deflection angle of the end portion of the probe may be selected by changing the length of the folded section 31 who

is pulled into the probe 1.

  Figures 8 to 11il of the accompanying drawings show embodiments of devices according to the invention comprising, in addition to the feature which allows the implantation of a graft or expandable prosthesis, a device ensuring a dilation of a stenosis in a vessel or canal prior to implantation of a supporting graft constituting a fixation device preventing

a new stenosis.

  Figure 8 is a schematic side elevation

  of such an embodiment of the device according to the invention.

  tion. The device comprises a central tube 123 surrounded by a flexible pipe 5 which comprises the section 51, 52 with double wall. The graft 2, compressed radially, is placed as previously described in the section 51,

  52 double wall and surrounds the central tube 123.

  A dilation balloon 125, sealingly attached at its two ends to the central tube 123,

  is disposed at the front end of the central tube 123.

  Although this feature is not represented

  As shown in detail in the drawing, the balloon 125 can be separately pressurized from the double-walled section 51, 52 by placing the central passage 127 of the tube 123 under pressure. The double-walled section 51, 52 can be pressurized by introducing a fluid under pressure into the annular space 129 formed between the tube

  123 and the piping 5 surrounding it.

  During operation of the device shown

  In Figure 8, the operations are summarized below.

  lowing. After introducing the device with the general reference 120 to the desired location for example of a Sanctuary vessel, the balloon 125 is inflated by separate pressurization. This inflation of the balloon is intended to widen the opening of the channel to the location of

  the stenosis to which the graft 2 must be implanted.

  After widening the opening to the desired location, the balloon 125 is deflated and the device 120 is moved forward so that the section 51, 52 to

  double wall takes the proper position in the

  bucket. The relative displacement of the central tube 123 and the flexible tubing 5, in the axial direction, then allows the release of the graft 2 at the desired location in the vessel so that it is permanently reinforced and for example a new stenosis can be avoided. After implantation, the device 120 is removed

of the ship.

  The embodiment of Figure 9 has the same operation as that of Figure 8 but the expansion balloon is placed behind the section 51, 52 double wall. In this embodiment, the swelling of the section 51, 52, intended to avoid friction, is performed with the pressurized fluid already used for swelling.

  ball 143, through the passage that makes them communicate.

  Moreover, the operation of the device of FIG. 9 is identical to that of FIG.

same benefits.

  Fig. 10 shows an embodiment in which a balloon 163 is disposed to surround the double-walled trunk 51, 52. This embodiment 160 includes a metallic or non-metallic core wire 167 surrounded by flexible tubing 165. A balloon 163 surrounds the flexible tubing 165 and is sealingly secured thereto, at the rear end, and at the front end.

of the outer wall 52.

  Two internal passages 169, 171 as shown

  11 in enlarged section, are formed in the flexible pipe 165 so that they allow the separate pressurization of the balloon and the double-walled section 51, 52. The passage 169 can be used for the arrangement of the central wire 167 and for the pressurization of the double-walled section 51, 52 so that the friction is reduced. The passage 171 may be used for pressurizing the expansion flask 163,

  separately from the section 51, 52 double wall. It is evidently

  It is possible to form three internal passages in the flexible pipe 165, two for the separate pressurization and one for the passage of a central guide wire. The operation of the device of FIG. 10 is identical to that of the devices of FIGS. 8 and 9, but no axial displacement of the device must be carried out after widening of the opening with the aid of the balloon 163, since the position widening of the opening is juxtaposed with the graft or prosthesis 2

  housed in the section 51, 52 double wall.

  The foregoing description relates to examples

  particular devices according to the invention. It should be noted that variants to the examples shown may be used. Thus, instead of introducing a fluid 22 into the space 25 and. the pressurization of this fluid, a lubricant can be disposed in the chamber, especially in the region between the walls 51, 52 of the double-walled section so that the friction

between them be reduced.

  It should further be noted in FIG. 1 that the details 8, 9, 10, 11, 12, 14, 15 can be omitted when the flexible tubing 5 or traction device attached thereto joins the rear end region. of the probe 1 so that the withdrawal movement of the flexible pipe 5 can be controlled from an accessible location. When the flexible tubing is formed of a material having a low coefficient of friction on itself, the lubricant placed between the walls 51, 52, of the double-walled section or the pressurization by a fluid of the space between these

  parcis can possibly be deleted.

  The invention thus relates to a new and very wide application device for implanting prostheses or grafts of the radially expandable type with automatic fixation. This device allows the implantation

2573986-

  grafts of almost any diameter, in the range of interest, ranging from small diameters of a millimeter or a few millimeters to diameters of several centimeters. The embodiment of the device according to the invention makes it possible, in particular, percutaneous peripheral as well as coronal transluminal angioplasty, in addition to the known characteristic of dilation by a balloon which gives the possibility of the implantation of a graft or prosthesis after enlargement of the the opening. We know

  for example, transcutaneous percutaneous angioplasty

  conventional lumen using the balloon device often causes a new stenosis at the location of the angioplasty, usually requiring elective graft surgery with coronary bypass,

  which is a very complicated and delicate operation. The utili-

  the small diameter version of the device according to the invention, as small as a few millimeters,

  does not require any surgical operation for the implan-

  transplantation in a vessel since a simple

  Percutaneous insertion can be used.

  The prosthesis used in the device according to the invention may be of any type insofar as it is radially expandable so that it can expand radially and attach itself automatically when released in a vessel or other leads. A particularly advantageous graft or prosthesis is described in British Patent Application No. 84.11 519. This graft or prosthesis comprises a flexible tubular body formed by a plurality of rigid but flexible individual filamentary elements, each arranged in a helix, the central axis of the body constituting their common axis, a number of elements having the same direction of winding but being offset axially with respect to each other and intersecting a number of elements themselves also axially offset from each other but having the sense opposite winding. The diameter of such a graft or prosthesis can be modified by axial displacement of the ends of the body relative to one another.

to the other.

  In one variant, the prosthesis used in the device described may be formed of a memory metal, that is to say a titanium-nickel alloy having mechanical memory properties. In this variant, the prosthesis in the radially contracted state retains this state, by cooling before its introduction while it is surrounded by the probe. When implanting after

  release at the desired location, the device and the

  thesis can be warmed by introducing a heating fluid in a channel formed in the probe, this heating causing the expansion of the prosthesis by triggering its

  memory properties. Examples of suitable alloys

  in such a prosthesis and who possess proprietary

  Mechanical memory tees are nickel-based alloys

  described in U.S. Patent No. 3,174,851.

  The operation of the device comprising this prosthesis

  is also identical to that of the other modes of

described.

Claims (14)

CLAIMS -   1. Implantation device by introducing, into a location that is difficult to access, a radially expandable tubular prosthesis (2), said device comprising this prosthesis (2) and, concentrically with it, a flexible probe (1) comprising a device (200) for maintaining the prosthesis (2) in a radially contacted state, and for releasing the prosthesis at the desired location, characterized in that the device for holding and releasing the prosthesis comprises a flexible tubing (5) concentrically surrounding the probe (1), a first end of the flexible pipe being connected to the probe (1), and the flexible pipe (5) being folded: on itself so that it forms a section (51, 52) double wall radially surrounding the prosthesis (2), which can be released by relative axial displacement of the   ends of the flexible pipe.   2. Device according to claim 1, characterized   in that an end surface (70) of the probe and the double-walled section (51, 52) of the piping form a cavity (57) in which the prosthesis (2) is housed during the introduction.   3. Device according to one of the claims   1 and 2, characterized in that the flexible tubing is sealed, the two ends of 1-a flexible tubing are tightly connected to the probe (1), and the surface of the probe adjacent to the flexible tubing is sealed between the connections of ends of the flexible tubing so that the flexible tubing and the probe form a chamber (25), and- a device (14, 22) is for transmitting a pressurized fluid to the chamber (25), so that the fluid reduces the contact pressure of the walls of the double-walled section (51, 52) of the flexible pipe and thus reduces the friction between the outer wall (52) and the inner wall (51) of the flexible pipe during their relative axial displacement.   4. Device according to any one of the   cations 1 to 3, characterized in that the fold (6) of the double-walled section (51, 52) of the flexible pipe is in front, in the direction (23) of introduction tansluminale device, the position to wherein the first end (7) of the flexible tubing is connected to the probe, whereby the prosthesis (2) can be released by applying a pulling force to the other end of the flexible tubing, the fold (6) ) moving along the prosthesis (2) towards the position of the connection of flexible tubing.   5. Device according to any one of the   cations 1 to 3, characterized in that the fold (6) of the double-walled section (51, 52) of the flexible pipe is placed behind in the direction (23) of transluminal introduction of the device, the position to wherein the first end (7) of the flexible tubing is connected to the probe, whereby the prosthesis (2) can be released by applying a pulling force to the other end of the flexible tubing, the fold (6) ) moving along the prosthesis (2) to the position   the connection of the flexible piping.   6. Device according to any one of the   cations 1 to 5, characterized in that the probe (1) comprises   at its front end, a sleeve (55) surrounding coaxial   the probe and against which is anchored the wall   dull (51) of the double-walled section, in that the sleeve can be moved axially relative to the probe, in that the sleeve, at its front end in the direction (23) of transluminum introduction of the device, has a   cavity (57) which, at the time of insertion, houses the end   mente of the prosthesis (2), and in that a flange (60) is fixed to the probe (1) and is arranged so that it forms a bearing shoulder of the end of the prosthesis (2) placed in the cavity, so that when the other end of the flexible pipe is removed, the sleeve (55) and the wall (56) of the cavity which surrounds it with   removed from the prosthesis (2).   7. Device according to any one of the   cations 1 to 6, characterized in that the probe (1) has   least one axial channel opening (4).   8. Device according to any one of claims 1 to 7, characterized in that the other end of the flexible pipe (5) is connected tightly to the probe (1) by a sealing device (10, 12 )   allowing axial displacement relative to the probe (1).   9. Device according to any one of the   1 to 8, characterized in that a lubricant is placed inside the flexible pipe (5), in   its double-walled section (51, 52).   10. Device according to any one of the   cations 1 to 9, characterized in that the outer wall   the double wall section is inflatable so that the opening   ture of the canal can be enlarged before implantation of the prosthesis.   11. Device according to any one of the   cations 1 to 9, characterized by an inflatable balloon placed in front of the double-walled section and intended to expand   the opening of the canal before implantation of the prosthesis.   12. Device according to any one of the   1 to 9, characterized by an inflatable balloon placed around the double-walled section and having substantially the same length as the balloon, the balloon being preferably independently controllable so as to widen the opening of the front channel implantation of the prosthesis.   13. Device according to any one of the   dications 1 to 9, characterized by an inflatable balloon placed behind the double-walled section and intended to widen the opening of the canal before the implantation of the prosthesis.   14. Device according to any one of the   preceding dications, characterized in that the prosthesis comprises a flexible tubular body composed of several individual elements in the form of rigid but flexible son, each wire having a helical configuration around a common axis formed by the central axis of the body, a number of these elements having the same direction of winding but being axially offset from each other and intersecting a number of elements also offset relative to each other but having the other direction of winding.